Shock absorber strut



July 21, 1936. K. w.wARREN 2,048,418

` sHocK ABsoRBER sTRUT Filed Feb. 18, 1952 .7 L INVENTOR.

/Z KENNETH W. WARREN A TTORNEY Patented July 21, 1936 YUNITED STATES SHOCK ABSORBER STRUT Kenneth W. Warren, South Bend, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application February 18, 1932, Serial No. 593,911,

16 Claims.

This invention relates to shock absorbers and more particularly to shock absorbing struts for airplanes.

Heretofore, shock absorbing struts 'for air- 5 craft have been provided with a single metering orifice. Struts of this type build up excessive loads at some point in the stroke. Others are provided with a single orifice and a metering lo pin coacting-therewith which provides a relatively smooth actlon. The cost of production of the latter type is relatively high. 4

It is the aim of the present invention to overcome these objections by providing a shock strut 15 affording smooth controlled action comprising but few parts constructed and arranged to absorb energy without building up excessive loads.

'mis invention broadly comprehends a shock absorber especially adapted for aircraft, incorporating both a liquid damping means for absorbing and dissipating'the initial landing shock, and a resilient means for supporting the load, eifective after the initial shock.

An important object of the invention is to provide relatively movable parts and means associated therewith including a plurality of spaced metering devices arranged to absorb and dissipate energy without building up excessive loads.

An important feature of the invention is a struthaving a movable piston therein provided with an oriiice and a series of diaphragms within the strut having orifices of successively varying area, the diaphragms being arranged back oi the piston and suitably spaced.

3 Another limportant feature is a taxying element arranged within the strut resulting in small over-all diameter, presenting a cleaner appearance, and aifording simplification of cowling attachment.

Yet another feature of the invention is the arrangement of the taxying element within the casing, so that it does not come into play until near the end of the piston stroke with the strut partially collapsed and the provision of a shoulder within the ,strut to limit the compression of the taxying spring. Other objects of the invention will appear from the following description taken in connection with' the drawing,which forms a part of this speciiication, and in which:

Figure l is a vertical sectional view of a shock absorbing strut embodying the invention, and

Figure Zis a fragmentary view of a strut illustrating a modification of the invention.

Referring to the drawing for more specific details of the invention, i represents a cylindrical casing having threaded or otherwise secured on one end a cap l2 provided with a clevice I4 for the attachment of a landing gear, not shown. The diameter of the casing -is slightly enlarged as shown at I6 to provide a shoulder I8 and the 5 other end of the casing has an enlarged portion 20 provided with a shoulder 22, the portion 20 being internally threaded as indicated at 24.

As shown, a coil spring 26 is slipped in the casing I8. This spring has one end seated on the cap Il and its other end extends beyond the shoulder I8 into the enlarged portion I6. When the spring is fully compressed it is confined within the area between the cap I4 andthe shoulder I8, as will be hereinafter explained.

A. cylindrical casing 28 has s' tably secured on one end a piston 30 provided with an oriiice 32 and the other end of the casing is closed by'cap 3l provided witha clevice 36 for attachment to the fuselage of an airplane, not shown. Arranged within the casing 28 in spaced relation, are diaphragms 38 and 40 provided with metering orifices 42 and 44 and positioned in the wall 4of the casing at a suitable point is a lling opening having threaded therein a plug 46. The metering orices' 32, 42 and M are graduated in size, the larger of the orifices being in the piston.

The cylindrical casing 28 telescopes the cylindricalA casing i0 with the piston 30 movable smoothly within4 the enlarged portion I6 of the' 30 casing I0. The casngs are secured together by ,a packing ring .I8 threaded in the enlarged portion 20 on the casing i0 with suitable packing material .'illY interposed between the packing ring and the shoulder 22.

When the strut is in an extended position, the cylindrical casing Il) is completely lled with oil to a level above the piston 30. When landing, the cylindrical casings III and 28 telescope. This action forces the oil in casing Ill through the or- 40 ifice 32 in the piston into the casing 28. As the velocity of the piston decreases, due to the absorption and dissipation of energy, the orifice area required is less, hence to successively de- 4crease the o rice area as required, the cylinder 45 28 has positioned therein, aseries of diaphragms provided with orifices, the areas of which are proportioned to'absorb and dissipate the necessary energy without building up excessive loads.

,4 A modication of the invention is illustrated in Figure 2. In this modification, the diaphragms 38 and 40 are removed from the cylindrical casing 28 and a piston 52 having an orice 54 is positioned on the spring 26. When the piston 30 has travelled a suilicient distance to abut the 55 cessively decreasing in area.

piston 52, carried by the spring 26, the orifice .54 will be brought into action and continue to the invention, the initial landing shock is eiiectively absorbed and dissipated by metering oil through oriiices of successively decreasing area, and the taxying shocks may be readily absorbed by the resilient means or the spring, the corn-A pression of which is limited by reason of the shoulder in the cylinder i0, providing a suitable abutment for the piston. l

Although this invention has been. described in connection with certain specific embodiments, the principles involved are susceptible to numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to'be limited only by the scope of -the appended claims.

Having thus described the various features of the invention, what I claim and desire to secure by Letters Patent is:

1 A' shock absorbing strut comprising telescopic members for absorbing and dssipating the initial shock of landing, including successively operative elements rigidly connected to one of said members and arranged to absorb and dissipate energy without building up excessive loads, and means for resiliently supporting the load effectiveafter the initial shock.

2. A shock absorbing strut comprising telescopic casings, liquid damping means within for absorbing and dissipating the initial shock including means rigidly connected to one of said casings for successively absorbing and dissipating energy uniformly throughout the stroke without building up excessive loads and means for resiliently supporting the load effective after the initial landing shock.

3. A shock absorbing strut comprising telescopic casings, means for Aabsorbing and dissipating the initial landing shock including a quantity of damping liquid partially illling the casings, means carried by one of the casings and rigidly fixed thereto for successively metering the liquid to absorb and dissipate the energy without building up excessive loads, and means for resiliently supporting the load eilective only after the initial landing shock.

4. A shock absorber comprising telescopic casings, an apertured piston carried by one of the casings, anda plurality of diaphragms arranged in spaced relation back of the piston, each diaphragm having an aperture of a diierent diameter.

5. A shock absorbing strut comprising telescopic casings, a piston carried by one of the casings, diaphragms in the casing carrying the piston, the piston and diaphragms each having an orifice, the orifices successively decreasing in area.

6. A shock absorbing strut comprising a tubular casing 'closed at one end, an apertured piston on the other end and a plurality of diaphragms arranged within the casing, the piston and dia-4 phragms each having an orifice, the orices suc-l 7. A shock absorbing strut comprising a tul bular casing closed at one end, a piston on the other end and a plurality of diaphragms in the casing, the piston and diaphragms each having an orifice, the orices successively varying in area.

y 8. A shock absorbing strut comprising a cylin- 5 drical casing having a double diametral bore providing a shoulder, a spring seated in the smaller means engageable with the piston for decreasing the area of the aperture.

l1i). A shock absorbing strut comprising telescopic casings, a spring positioned in one of the casings, a piston carried by the other casing, a movable diaphragm on the spring, the piston and diaphragm having orices of different diameters.

11. A shock absorbing strut comprising telescopic casings, an apertured piston carried by one of the casings, a spring positioned in the other casing, and a movable apertured diaphragm supported by the spring.

12. A shock absorbing strut comprising telescopic cylindrical casings, one of the casings having a double diametral bore, a shoulder provided by the double diameter bore, a spring in the smaller bore, .a movable apertured diaphragm 35 supported by the spring above the shoulder, an aperturedpiston secured to the inner end of the other casing adaptable for movement in the larger bore and for cooperation with the movable diaphragm.

13. A shock absorbing` strut comprising telescopic casings, a spring positioned in one of the casings, an apertured piston on the inner end of the other casing, and apertured diaphragms arranged within one of the casings in spaced relation back of the piston, the apertures in the piston and diaphragms having diierent areas.

14, A shock absorbing strut comprising telescopic casings, one of the casings closed at one end and provided with a double diametral bore, a shoulder formed by the double diametral bore, a spring seated in the smaller bore and extending into the larger bore, another casing closed at one end, a piston on the other end adaptable for movement in the larger bore, diaphragms in the second casing arranged in spaced relation and having oriiices successively decreasing in area.

15. A shock absorbing strut comprising means for absorbing and dssipating the initial shock 60 of landing, including aplurality of successively operative elements arranged inseries and rigid spaced relation to absorb and dissipate energy without building up excessive loads.

16. A shock absorbing strut comprising telescopic casings, means for absorbing and dissipating the initial landing shock including a quantity of damping liquid partially iilling the casings, and a plurality of means carried by and rigidly sevcured to one of the casings for successively metering the liquid to absorb and dissipate the energy CERTIFICATE CF CORRECTION.

Patent N. 2,048,418. July 21, 1936.

KENNETH w. WARREN.

It is hereby certfiedthat error appears in the printed specification' of the abovenumbered patent requiring Correction as follows: Page 12,v second column, line '70D` claim f3.6, after the -Word "casings" insert arranged in series; and that the said Letters Patent should be read vwith, this Correction therein that the saule may conform to therecord of the case ign the Patent Office. v

Signed and sealed this 13th day of July, A. l?. 1937.

Henry Van Arsdale Iseal) Acting Commi''brir-of Patents. 

